1. Field of the Background
The present invention generally relates to window shades, and more particularly to a lift system for use with, for example, a Roman shade.
2. Description of the Background
Various types of window coverings are known, including roller shades and Roman shades, which are also generally referred to as blinds. Roman shades typically comprise a shade suspended from a headrail. The shading material, which may be formed from a variety of materials including paper, cloth, other fabrics, and plastic and wood members, is typically moved to a stowed configuration and maintained in such configuration by a cord attached to the shade at or near its bottom edge. The shade is then deployed by letting out the cord to lower the bottom edge and, with it, the remainder of the shade. The cord is typically disposed along an outer face of the shade, and may be attached to spaced portions of the shade to promote uniform folding of the shade as the shade is being raised by the cord.
The cord of such a blind can attract the attention of a child. An infant or toddler can become entangled in a loose cord, and may be strangled by placing his/her head between the cord and the shade. Therefore, improvements in blinds have been developed to reduce the risk of such tragedies. A blind with a safety arrangement is disclosed in Lin U.S. Patent Publication No. 2005/0092448. The blind comprises a headrail, a brake mechanism proximate the headrail, a pair of cord portions that pass through the brake mechanism, and a shade cloth. The shade cloth has a lower end secured to ends of the cord portions and the cord portions extend upwardly adjacent a rear face of the shade cloth through cord covers formed of a soft material, such as yarn. A plurality of spaced positioning elements are stitched to the cord cover and to the shade cloth. Pulling ends of the cord portions adjacent a front face of the shade cloth causes the positioning elements, except the topmost positioning element, to move upwardly, thereby causing the shade cloth to wrinkle upwardly. Also, the cord covers are contracted together. Lin notes that: “a dangerous ring will not be formed by the cord and the cord covers in operation.” However, Lin does not disclose the structure or configuration of the positioning elements, and therefore, does not teach in sufficient detail how such a blind may be satisfactorily constructed with materials that are aesthetically pleasing, easy to operate, and long-lasting in use. In this regard, the use of a material, such as a low-strength yarn, for the cord covers, can lead to wear and failure of the cord covers at the point(s) of attachment of one or more of the positioning elements to the shade cloth, thereby resulting in the possibility that the a dangerous loop could be formed.
The blind disclosed in Lin also requires a user to pull ends of the cord portions in order to raise and lower the shade. This arrangement results in exposed cords accessible from the front of the shade by a child, which is undesirable.